// Copyright 2016 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef V8_COMPILER_BYTECODE_LIVENESS_MAP_H_
#define V8_COMPILER_BYTECODE_LIVENESS_MAP_H_

#include "src/base/hashmap.h"
#include "src/bit-vector.h"
#include "src/zone/zone.h"

namespace v8 {
namespace internal {

    class Zone;

    namespace compiler {

        class BytecodeLivenessState : public ZoneObject {
        public:
            BytecodeLivenessState(int register_count, Zone* zone)
                : bit_vector_(register_count + 1, zone)
            {
            }

            const BitVector& bit_vector() const { return bit_vector_; }

            BitVector& bit_vector() { return bit_vector_; }

            bool RegisterIsLive(int index) const
            {
                DCHECK_GE(index, 0);
                DCHECK_LT(index, bit_vector_.length() - 1);
                return bit_vector_.Contains(index);
            }

            bool AccumulatorIsLive() const
            {
                return bit_vector_.Contains(bit_vector_.length() - 1);
            }

            bool Equals(const BytecodeLivenessState& other) const
            {
                return bit_vector_.Equals(other.bit_vector_);
            }

            void MarkRegisterLive(int index)
            {
                DCHECK_GE(index, 0);
                DCHECK_LT(index, bit_vector_.length() - 1);
                bit_vector_.Add(index);
            }

            void MarkRegisterDead(int index)
            {
                DCHECK_GE(index, 0);
                DCHECK_LT(index, bit_vector_.length() - 1);
                bit_vector_.Remove(index);
            }

            void MarkAccumulatorLive() { bit_vector_.Add(bit_vector_.length() - 1); }

            void MarkAccumulatorDead() { bit_vector_.Remove(bit_vector_.length() - 1); }

            void MarkAllLive() { bit_vector_.AddAll(); }

            void Union(const BytecodeLivenessState& other)
            {
                bit_vector_.Union(other.bit_vector_);
            }

            bool UnionIsChanged(const BytecodeLivenessState& other)
            {
                return bit_vector_.UnionIsChanged(other.bit_vector_);
            }

            void CopyFrom(const BytecodeLivenessState& other)
            {
                bit_vector_.CopyFrom(other.bit_vector_);
            }

        private:
            BitVector bit_vector_;

            DISALLOW_COPY_AND_ASSIGN(BytecodeLivenessState);
        };

        struct BytecodeLiveness {
            BytecodeLivenessState* in;
            BytecodeLivenessState* out;

            BytecodeLiveness(int register_count, Zone* zone);
        };

        class V8_EXPORT_PRIVATE BytecodeLivenessMap {
        public:
            BytecodeLivenessMap(int size, Zone* zone);

            BytecodeLiveness& InitializeLiveness(int offset, int register_count,
                Zone* zone);

            BytecodeLiveness& GetLiveness(int offset);
            const BytecodeLiveness& GetLiveness(int offset) const;

            BytecodeLivenessState* GetInLiveness(int offset)
            {
                return GetLiveness(offset).in;
            }
            const BytecodeLivenessState* GetInLiveness(int offset) const
            {
                return GetLiveness(offset).in;
            }

            BytecodeLivenessState* GetOutLiveness(int offset)
            {
                return GetLiveness(offset).out;
            }
            const BytecodeLivenessState* GetOutLiveness(int offset) const
            {
                return GetLiveness(offset).out;
            }

        private:
            base::TemplateHashMapImpl<int, BytecodeLiveness,
                base::KeyEqualityMatcher<int>, ZoneAllocationPolicy>
                liveness_map_;
        };

    } // namespace compiler
} // namespace internal
} // namespace v8

#endif // V8_COMPILER_BYTECODE_LIVENESS_MAP_H_
